Investigation of the alpha particle-induced electron-ion temperature nonequilibrium burning process in inertial confinement fusion

The achievement of thermal nuclear burn at the National Ignition Facility represents a significant milestone in the field of fusion science and engineering. This study uses the double-temperature model to investigate the degree of alpha particle-induced electron-ion temperature nonequilibrium and the final burn fraction in the inertial confinement fusion (ICF) burn process. The time evolution of the burn process with typical inertial confinement fusion parameters reveals that the nonequilibrium degree shows a trend of initially decreasing and then increasing, with the final burn fraction in the double-temperature model being higher than that in the single-temperature model. The investigation of the dependence of the burn fraction on initial parameters reveals that the burn fraction of the single-temperature and double-temperature models intersect at a characteristic ion temperature of about 45 keV, which is attributed to the dependence of the fusion rate on the ion temperature. The relationship between the nonequilibrium factor delta(Nf ) and burn fraction f(b) in the electron heat conduction loss-dominant region satisfies ( delta(Nf )- 1 ) / f(b) approximate to const. Furthermore, the tritium fraction required to achieve the maximum burn fraction decreases as the initial areal density increases when the initial temperature is equal to 5 keV and the fuel is ignited. With different deuterium-tritium ratios, the extended burn fraction formula fits both the single-T and the double-T model results well under typical ICF parameters. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license